1: <?php
  2: /**
  3:  * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
  4:  * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
  5:  *
  6:  * Licensed under The MIT License
  7:  * For full copyright and license information, please see the LICENSE.txt
  8:  * Redistributions of files must retain the above copyright notice.
  9:  *
 10:  * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 11:  * @link          https://cakephp.org CakePHP(tm) Project
 12:  * @since         3.0.0
 13:  * @license       https://opensource.org/licenses/mit-license.php MIT License
 14:  */
 15: namespace Cake\Datasource;
 16: 
 17: use Cake\Cache\Cache;
 18: use Cake\Cache\CacheEngine;
 19: use RuntimeException;
 20: use Traversable;
 21: 
 22: /**
 23:  * Handles caching queries and loading results from the cache.
 24:  *
 25:  * Used by Cake\Datasource\QueryTrait internally.
 26:  *
 27:  * @see \Cake\Datasource\QueryTrait::cache() for the public interface.
 28:  */
 29: class QueryCacher
 30: {
 31: 
 32:     /**
 33:      * The key or function to generate a key.
 34:      *
 35:      * @var string|callable
 36:      */
 37:     protected $_key;
 38: 
 39:     /**
 40:      * Config for cache engine.
 41:      *
 42:      * @var string|\Cake\Cache\CacheEngine
 43:      */
 44:     protected $_config;
 45: 
 46:     /**
 47:      * Constructor.
 48:      *
 49:      * @param string|\Closure $key The key or function to generate a key.
 50:      * @param string|\Cake\Cache\CacheEngine $config The cache config name or cache engine instance.
 51:      * @throws \RuntimeException
 52:      */
 53:     public function __construct($key, $config)
 54:     {
 55:         if (!is_string($key) && !is_callable($key)) {
 56:             throw new RuntimeException('Cache keys must be strings or callables.');
 57:         }
 58:         $this->_key = $key;
 59: 
 60:         if (!is_string($config) && !($config instanceof CacheEngine)) {
 61:             throw new RuntimeException('Cache configs must be strings or CacheEngine instances.');
 62:         }
 63:         $this->_config = $config;
 64:     }
 65: 
 66:     /**
 67:      * Load the cached results from the cache or run the query.
 68:      *
 69:      * @param object $query The query the cache read is for.
 70:      * @return \Cake\Datasource\ResultSetInterface|null Either the cached results or null.
 71:      */
 72:     public function fetch($query)
 73:     {
 74:         $key = $this->_resolveKey($query);
 75:         $storage = $this->_resolveCacher();
 76:         $result = $storage->read($key);
 77:         if (empty($result)) {
 78:             return null;
 79:         }
 80: 
 81:         return $result;
 82:     }
 83: 
 84:     /**
 85:      * Store the result set into the cache.
 86:      *
 87:      * @param object $query The query the cache read is for.
 88:      * @param \Traversable $results The result set to store.
 89:      * @return bool True if the data was successfully cached, false on failure
 90:      */
 91:     public function store($query, Traversable $results)
 92:     {
 93:         $key = $this->_resolveKey($query);
 94:         $storage = $this->_resolveCacher();
 95: 
 96:         return $storage->write($key, $results);
 97:     }
 98: 
 99:     /**
100:      * Get/generate the cache key.
101:      *
102:      * @param object $query The query to generate a key for.
103:      * @return string
104:      * @throws \RuntimeException
105:      */
106:     protected function _resolveKey($query)
107:     {
108:         if (is_string($this->_key)) {
109:             return $this->_key;
110:         }
111:         $func = $this->_key;
112:         $key = $func($query);
113:         if (!is_string($key)) {
114:             $msg = sprintf('Cache key functions must return a string. Got %s.', var_export($key, true));
115:             throw new RuntimeException($msg);
116:         }
117: 
118:         return $key;
119:     }
120: 
121:     /**
122:      * Get the cache engine.
123:      *
124:      * @return \Cake\Cache\CacheEngine
125:      */
126:     protected function _resolveCacher()
127:     {
128:         if (is_string($this->_config)) {
129:             return Cache::engine($this->_config);
130:         }
131: 
132:         return $this->_config;
133:     }
134: }
135: